Galatians 2:11-12

Now when Cephas (Peter) came to Antioch, I opposed him face to face [about his conduct there], because he stood condemned [by his own actions]. Before certain men came from James, he used to eat [his meals] with the Gentiles; but when the men [from Jerusalem] arrived, he began to withdraw and separate himself [from the Gentile believers], because he was afraid of those from the circumcision.